You create mesh models using a third-party 3D modeling tool. If you're a seasoned content creator, you may already be familiar with tools such as 3ds Max, Maya, Blender, or other popular professional tools; Google's SketchUp also provides a low barrier to entry for aspiring 3D modelers. Any 3D modeling software will work, as long as it can output models in COLLADA (.dae) format. Note: Second Life uses COLLADA 1.4.

A list of software that has COLLADA support can be found at COLLADA.org Products Directory
A very extensive list of 3d software can be found at 3Dlinks.com under the software section. Which of either the COLLADA or 3Dlinks items
will work with Second Life is not known, but at least it is a starting point to look.

To learn more about some of the available 3D modeling tools, visit the 3D software guide created for use with sculpted prims. Most of the tools that work for sculpted prims should work with mesh, as long as they can export models in COLLADA format.

Collada(DAE) Supported Programs for Mesh

Notes on mesh support for specific versions of various applications - please update if you have additional information: